Watertanks containing only fishes is a dull watertanks and no ornament to a house. First thing that we have to think about is covering the bottom of the watertanks with sand or gravel in which the plants can be placed and where, eventually, they will root themselves.Some people like to place a layer of leaves or peat moss beneath the sand. We should be careful to choose only well rotted oak or beech leaves as many others leaves contain substances which, although they may not harm the plants, are poisonous to the fishes. For common average aquarist, however, there is little need to bother with peat moss or leaves. Sand or gravel will be enough as the fishes, in the course of nature, will fertilize the plants.For general purposes of covering the bottom and making a place for the plants there is nothing to beat the coarse gravel which can be obtained from any aquarium supply shop. For an extra amount, you could be little fancy with white quartz gravel which will look very pretty when the watertanks is newly set up. But unfortunately those white quartz gravel will become discolored in a short time, so that it will be difficult to tell it from ordinary and cheaper gravel.Never use sea sand on the bottom of the aquarium. It’s too fine and is almost impossible to keep clean. Also it may contain lime which is not soluble in salt water, will make it too hard or alkaline for our fishes.Shortly we will find that we need far more gravel than we supposed on looking at our watertanks. For a ten gallon watertanks, for instance we will require at least five pounds and more. First things to do after we buy gravel is to wash it. Pour the gravel into a bucket and fill the bucket up with water. Stir the gravel around thoroughly and then pour off the cloudy water. This action should be repeated several times until the water remains clear when you stir. The gravel is then ready for use.